In November 1991 in Prague, in a conversation between the Polish historian and intellectual, Adam Michnik, and the late Czech president and playwright, Vaclav Havel, Michnik remarked that with communism set to expire and Yugoslavia having just erupted in war, a "coarse and primitive nationalism" had replaced communism as the great enemy. But last May in The New Republic, the historian and columnist Anne Applebaum wrote that a public-spirited nationalism was exactly what Ukrainians needed to buttress their own democracy. Are Michnik and Applebaum in disagreement? Not really. Michnik is writing about nationalism in one historical context; Applebaum is writing about nationalism in another context.

The same observation can be made about imperialism. In the 1990s when Yugoslavia was in violent disarray a number of writers, despairing of the effect of ethnic nationalism, waxed sentimental about the relative multiethnic tolerance of the Habsburg Empire in Europe. Imperialism then did not seem so bad. To wit, it was not so much multiethnic Ottoman imperialism that led to the Armenian genocide as monoethnic Young Turk nationalism. Of course, now it is different. With Russian imperialism on the march and the 100th anniversary of World War I this week — a war that saw empires collide in bloody cataclysm — imperialism is under strong attack. The civilizational glories of the Han, Achaemenid, Mauryan, Songhai and many other empires throughout history seem not to be considered, if even known about.

As to whether imperialism is good or bad, it all depends on which type of imperialism one is talking about during which time in history and what aspect of which empire. The truth is that both nationalism and imperialism are such broad categories that they can be good or bad depending upon the cultures and circumstances involved. After all, nationalism and imperialism have been present in one form or another throughout much of the world and throughout much of history.

Because Michnik and Applebaum are talking about specific attributes of nationalism, they are not prone to the mistakes of others who condemn whole categories outright. Neither nationalism nor imperialism is altogether good or altogether evil. For nationalism and imperialism are not primarily ideologies but rather organizing principles of group pride and of vast territorial administration. Ideologies, on the other hand, entail a degree of abstraction and are in the main utopian. German Nazism and Soviet Communism were utopian movements that combined nationalism with imperialism. That's part of what made them unique. The point is to beware of easy comparisons and judgments. To put the nationalism of civil society demonstrators in Kiev's Maidan in the same category with the nationalism of Vladimir Putin's Russia is nonsense; so is condemning the Habsburgs as imperialists just because the Nazis were also.

Not only can nationalism and imperialism play out differently depending upon the circumstances, so obviously can broad phenomena such as religion and democracy. For example, it is a mere commonplace to state that the Christianity of evangelicals in the American Midwest is different from that of Lebanese Phalangists during the civil war of the 1970s and 1980s, just as the aesthetic and moderate Islam of Morocco and Oman is different from that of the Taliban in Afghanistan and Pakistan. Democracy in America is different from that in Iraq. And while Deng Xiaoping may have been a ruthless dictator, his accomplishments in China put him in an entirely different category from Saddam Hussein and Bashar al Assad.

But we know all that!, you might say. Yet apparently we don't. For spreading democracy no matter what the local circumstances has been a philosophical feature of a significant branch of the American foreign policy establishment for decades now. Of course, one can argue that since in most circumstances, imperialism is bad and democracy is good, we will oppose the former and support the latter. But while that might work as a broad consensus-driven goal, the messy specifics require more nuance in application.

For example, there are clearly imperial-like aspects to the worldwide deployment of American warships and fighter jets, and yet we value those assets as a global force for good just the same. And while democracy might be a good in and of itself, no responsible policymaker in Washington should ever want to topple the monarchies in Saudi Arabia, Oman and Morocco. Again, beware of simple categories.

The point is to get away from abstractions and deal in the concrete world at the ground level. Journalists and historians are generally better at this than political scientists and others who adhere to certain conceptual viewpoints of human society. Journalists and historians are driven by the very messiness of reality, along with the many contradictions, and are therefore less prone to so-called laws of how interstate relations play out. They also recognize the signal importance of personalities in world history so that Winston Churchill, though an imperialist, was arguably the greatest man of the 20th century and Deng Xiaoping, while a dictator, was also one of the great men of that century.

Concepts such as nationalism and imperialism will continue to be highly relevant in upcoming debates about U.S. foreign policy because, in arguing about them, we define what the values of American foreign policy should be. A policy that seeks to rejuvenate American nationalism would place a greater emphasis on domestic concerns such as health care, the preservation of the middle class and the revitalization of infrastructure. Immigration reform would be needed to ensure a dynamic and relatively youthful society for decades to come. Meanwhile, America, in this nationalistic view, would adopt a more modest posture in world affairs. In a brilliantly crafted essay in the May/June issue of The National Interest, "The Case for American Nationalism," Michael Lind of the New America Foundation argues along these lines.

An imperialist view might seek to rejuvenate American society through a reduction of the tax burden and immigration reform. At the same time, in this view, America would adopt a more robust posture around the globe in order to continue to ensure safe and secure sea lines of communication for the sake of a liberal world order, and to support American allies against the imperialism of non-democratic states.

The two views are not mutually exclusive and could be combined in several ingenious formulations. Because America has been both a nation and an empire of sorts, the debate will go on — even as journalists and historians hopefully provide a reality check.

Robert D. Kaplan was Stratfor's Chief Geopolitical Analyst from March 2012 through December 2014. He is currently a Senior Fellow at the Center for a New American Security in Washington, D.C., and has been a foreign correspondent and contributing editor at The Atlantic, where his work has appeared for three decades. In 2009, he was appointed to the Pentagon's Defense Policy Board, which advised former U.S. Secretary of Defense Robert Gates on key issues. Mr. Kaplan served on the board through 2011. From 2006 to 2008, he was the Class of 1960 Distinguished Visiting Professor in National Security at the U.S. Naval Academy.